The research proposed here is aimed at identifying the abilities that underlie skilled reading and writing by prelingually and profoundly hearing-impaired children and adults. Because most of these deaf individuals attain reading levels far below those of their normally-hearing counterparts, it is of great importance to discover what abilities enable some deaf persons to succeed. By identifying the underlying cognitive abilities employed during reading by the minority of deaf persons who are successful readers, this research can be expected to yield results that will signficantly influence educational planning for deaf children. The proposed investigation is based on a substantial body of psychological research indicating that the ability to abstract linguistic segments and to hold them efficiently in short-term memory is crucial for success in learning to read. The proposed set of experiments will present words and printed text to deaf and hearing subjects. The experiments will examine the relative contributions of speech-based and sign-based encoding strategies to success in acquiring beginning reading and attainment of mature reading skills by deaf children and adults. The reseach is designed to determine whether the sign systems commonly used in the classrom with deaf children may be exploited as a substitute for the speech code in the acquisition of skilled reading. Four specific questions are asked: (1) Is the use of speech-based code as closely correlated with beginning reading success for deaf children as it is for hearing children? (2) What strategies do skilled (adult) deaf readers use in reading? (3) Can a sign-based code serve as a substitute for a speech-based code in supporting the acquisition of written language? (4) What cognitive abilities underlie spelling for deaf children and adults?